On-machine-seamable multi-axial press fabrics for the press section of papermaking machines are known in the art. Such press fabrics are generally made from a base fabric layer assembled by spirally winding a fabric strip in a plurality of contiguous turns which are joined together along neighboring adjacent edges of the strip to form an endless base fabric tube. This tube is then flattened to produce first and second fabric plies or layers which are then joined to one another. A seam is formed by removing cross-direction yarns from each turn of the fabric strip at the folds located at the cross-machine direction (CMD) extending edges of the fabric. This results in a plurality of seaming loops being formed by the folded over generally machine direction (MD) extending yarns in the fabric which can be joined by the insertion of a pintle following the interdigitation of the seaming loops from the opposed fabric ends.
Such arrangements are described in U.S. Pat. Nos. 6,117,274 and 6,776,878. Additionally, in order to achieve a desired void volume, multiple layers of fabric may be joined together. Seaming loops are provided at the ends of the multiple fabric layers and can be joined by interdigitating the seaming loops to form multiple passages through which multiple pintles are then passed.
In addition to the fabrics described in the above-referenced prior art patents, FIGS. 1 and 2 also show a known commercial spiral wound multi-axial base fabric for use in a press fabric for the press section of a papermaking machine. In the known multi-axial on-machine seamable laminated press fabrics, the seams have been problematic due to the unevenness of the folded generally MD extending warp yarns that are used to form the seaming loops. As shown in FIGS. 1 and 2, in a typical arrangement, these MD warp yarns are arranged at non-uniform positions across the fabric thickness, depending upon the weave and the fold location used to form the seam. This results in an uneven path for insertion of the pintle in order to seam the fabric on the paper making machine. This can also result in an unacceptable discontinuity in the fabric at the seam due to fabric tension at the seam being carried in a non-uniform manner based on the various positions of the generally MD extending warp yarns across the height of the fabric.
It would be desirable to provide a base fabric for a multi-axial seamed papermaking fabric as well as a multi-axial seamed papermaking fabric that provides a more uniform seam that can be more easily assembled on papermaking machine with reduced time and cost savings.